1. Field of The Invention
The present invention relates to a rotary locator with differential position in a pen. In particular, the present invention relates to a rotary locator with differential position in a pen, in which an eccentric cam is actuated to perform a relative movement of a follower stem and a differential position so as to displace and locate the center stick in the pen.
2. Description of Related Art
A pen is used for writing and sketching since very early years. According to the industry and business progress and technology development, the pen has presented multiple aspects already. General speaking, the pen can be classified into three categories based on the structure and the operation way. One of these three categories is the nib part of the center stick in the pen is enclosed by a pen cap. Another one is the center stick can be extended outward and retreated inward by way of turning the penholder. The last one is the center stick can be extended outward and be retreated inward by way of push device.
The types of pen with turned penholder and with push device are much popular and have been keeping be used till now. Because the nib part of the center stick can be received in the pen automatically for these two types of pen, no need of the pen cap to cover the nib part for clipping to clothes and preventing from staining the clothes.
For the push type of pen, it can be divided into that with bounce device and with lock device respectively. The bounce device comprises a press cap and a bounce key under the press cap. The bounce key is moved downward synchronously to result in the rotary key thereof pressing against a rib part at the top thereof. Thus, a differential position is formed to squeeze the center stick and a spring in the penholder so as to expose the nib part of the center stick for writing. The lock device comprises a press stem with a lateral elastic tenon. The elastic tenon can move away the first locking recess and engages with the second locking tenon to form a differential position as soon as the press stem is pushed downward. Then, the center stick and the spring in the penholder are squeezed to expose the nib part for writing.
The preceding two push types of pens cause the center stick in the penholder to move outward and inward mainly by way of the push device constituting a differential position and a locating relation. Therefore, it can be entitled "push type of locator with differential position". Accordingly, how to breakthrough the conventional locator with differential position is a subject worth the supplier to consider.